BIO 201 Homework 1

They have the same number of electrons in their outermost shells.

Nitrogen and Phosphorous

Hydrogen Bonds

-Bonds between charged molecules or portions of a molecule -weak attraction between slightly charged parts of molecules, which are readily broken and reformed -bonds between water molecules

Ionic bonds

-Electrons are transferred between two atoms creating positively and negatively charged atoms, which are then attracted to one another. -Na+ + Cl- -> NaCl

Covalent Bonds

-Strong chemical bond due to the sharing of electrons. -Bonds between hydrogen and oxygen atoms within a water molecule.

Hydrogen has a total of __ e-, __ are in the valence shell and __ lie in the p orbitals

1,1,0

Rank the following levels of biological organization from the lowest level of complexity to the highest level of complexity

1. Oxygen atom 2. DNA molecule 3. Nerve cell 4. Nervous tissue 5. Brain 6. Fish 7. School of fish 8. Group of dolphins, fish, and algae 9. Pacific Ocean and inhabitants 10. Planet Earth

Carbon has a total of __ e-, __ are in the valence shell and __ are in the 1s orbital

6,4,2

Nitrogen has a total of __ e-, __ are in the valence shell and __ lie in the p orbitals

7,5,3

Carbon 12, 13, and 14 are isotopes of the same element. They share the same place on the periodic table but possess varying numbers of neutrons. If carbon 12 has 6 protons, how many neutrons will carbon 14 have?

8

Adding NH3 (ammonia) to water makes NH4+. What will be the general pH of this new solution, and what will happen to the ion concentrations?

Alkaline; decreased H+ ions and increased OH-

They have two electron shells

Carbon and Nitrogen

The bonds between water molecules are stable.

False

Their outermost electron shell is full

Helium and Argon

They have one electron shell

Hydrogen and Helium

They have three electron shells

Sodium and Chlorine

6 CO2 + 6 H2O + Light → C6H12O6 + O2 is an example of a chemical reaction. What is occurring during this reaction?

Substances are changed into other substances by the making or breaking of chemical bonds.

A basilisk lizard was brought into a lab. Scientists provided a pool of ethanol, a liquid that has less polar bonds than water. What will probably happen when the lizard attempts to run over the surface of the ethanol pool?

The lizard will not be able to run over the surface of the ethanol pool, it will sink into the ethanol.

If running over the surface of the water allows the basilisk lizard to escape predators, what assumption is made about the predators?

The predators cannot swim

The polar covalent bonds between hydrogen and oxygen atoms within a water molecule create slight positively and negatively charged ends to the molecule.

True

A polar covalent bond is created when

bonded atoms have unequal pull on the shared electron, so that the electron spends more time around one atom than the other.

A hydrogen atom of one water molecule binds via a hydrogen bond to a hydrogen atom of another water molecule.

false

Bonds between water molecules are stronger than the bonds between the atoms within a water molecule.

false

Ice is denser than liquid water at all temperatures.

false

Stable blood serum has a pH of around 7.4. The release of bicarbonates as a buffer to maintain this pH in a body with high hydrogen levels would cause the pH to move

from acidic to slightly alkaline.

What anatomical adaptation allows basilisk lizards to run across the surface of the water?

it has feet with a large surface area

The unequal sharing of electrons between oxygen and hydrogen atoms within a water molecule makes water a ____ molecule.

polar

The reason water behaves in this manner is because the ___ charge on the hydrogen end of the water molecule is attracted to the negative charge of a polar molecule, while the ___ charge of the oxygen end of the water molecule is attracted to the positive side of a polar molecule.

positive, negative

As a result of the elctron configuration of a water molecule, water is a great ___ because water can break up and surround a ___, as long as it is not nonpolar, dissolving it into solution.

solvent, solute, nonpolar

As temperature drops the bonds between water molecules are less likely to break.

true

The fluid nature of water is due to hydrogen bonds continually breaking and reforming.

true